Fawzia Bardag-Gorce
Los Angeles Biomedical Research Institute, USA
Title: The ubiquitin proteasome pathway in Cultured Oral Mucosa Epithelial Cell Sheet (CAOMECS) for ocular surface reconstruction
Biography
Biography: Fawzia Bardag-Gorce
Abstract
PURPOSE: This study focuses on characterizing proteasomes in corneal epithelial cells (CEC) and in cultured autologous oral
mucosal epithelial cell sheets (CAOMECS) used to regenerate the ocular surface.
METHODS: Limbal stem cell deficiency (LSCD) was surgically induced in rabbit corneas. CAOMECS was engineered and grafted
onto corneas with LSCD to regenerate the ocular surface. RESULTS: LSCD caused an increase in inflammatory cells in the ocular
surface, an increase in the formation of immunoproteasomes (IPR), and a decrease in the formation of constitutive proteasome
(CPR). Specifically, LSCD-diseased CEC (D-CEC) showed a decrease in the CPR chymotrypsin-like, trypsin-like and caspase-like
activities, while healthy CEC (H-CEC) and CAOMECS showed higher activities. Quantitative analysis of IPR inducible subunit (B5i,
B2i, and B1i) were performed and compared to CPR subunit (B5, B2, and B1) levels. Results showed that ratios B5i/B5, B2i/B2 and
B1i/B1 were higher in D-CEC, indicating that D-CEC had approximately a two-fold increase in the amount of IPR compared to
CAOMECS and H-CEC. Histological analysis demonstrated that CAOMECS-grafted corneas had a re-epithelialized surface, positive
staining for CPR subunits, and weak staining for IPR subunits. In addition, digital quantitative measurement of fluorescent intensity
showed that the CPR B5 subunit was significantly more expressed in CAOMECS-grafted corneas compared to non-grafted corneas
with LSCD.
CONCLUSION: CAOMECS grafting successfully replaced the D-CEC with oral mucosal epithelial cells with higher
levels of CPR. The increase in constitutive proteasome activity is possibly responsible for the recovery and improvement in the treated
corneas. Supported by Emmaus Life Sciences Inc.